best opening??

You can't really decide the openings. Make common opening moves and play them. Eventually, you and your opponent will cover the basics.

Try the Muzio Gambit first then the Ruy Lopez and all the double-king-pawn games first.

Then adjust it to suit your taste.

For me Ruy Lopez

I like Colle System and Queen's gambit, they are goods one.

Or the one that stockfish says.

all the gambits are good

all the non-gambits just aren't as good

For low-rated opponents, you have the advantage of people who don't really know how to avoid opening tricks and traps and deal with them. You can even have the luxury of choosing gambits to throw your opponent off guard.

So you should be choosing some trappy openings but not that much or if they know them you get a comfortable position. I recommend the Greco Attack, it's wild enough to bring your opponent in a deep dark forest where they don't know anything about positions you perfectly know. And for Black, I suggest you the Scandinavian defense but not 2.Qxd5 but rather 2.Nf6, which seems like your opponent can easily hold on to the pawn but you got them into your trap!

These are my personal advice, but you can choose whatever you want. I prefer anything to throw your opponent off their game with gambits or aggressive openings.

There are no best openings, programs will find a way to crush them almost everytime.
Try any 1.d4 or 1.e4 Opening, program says:
I am going to crush this.
After a certain rating barrier, you can try anything they will come up with solutions you wouldnt dream of......
In Otb you have to be motivated, otherwise you will also just get crushed.....

e2-e4
Kg1-f3
Bf1-d4
c2-c3
castle